Matrix liquid crystal display

ABSTRACT

The invention relates to a matrix liquid crystal display containing integrated non-linear elements and a liquid crystal mixture which has a particularly high resistivity.

The invention relates to a matrix liquid crystal display containing

-   -   two plane parallel support plates which together with a frame        form a cell,    -   integrated non-linear elements for switching individual picture        elements on the support plates and    -   a nematic liquid crystal mixture which is present in the cell        and has a positive dielectric anisotropy and high resistivity,        the liquid crystal mixture being based on the following        components:

-   a) at least 10% by weight of a liquid-crystalline component B    comprising one or more compounds having a dielectric anisotropy of    more than +1.5,

-   b) up to 90% by weight of a liquid-crystalline component A    comprising one or more compounds having a dielectric anisotropy of    −1.5 to +1.5 of the general formula I    in which

-   R¹ and R² are each, independently of one another, n-alkyl,    ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms,    -   the rings A¹, A² and A³        -   are each, independently of one another, 1,4-phenylene, 2- or            3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or            1,4-cyclohexenylene,    -   Z¹ and Z² are each, independently of one another,        -   —CH₂CH₂— or a single bond, and    -   m is 0, 1 or 2, and

-   c) 0 to 20% by weight of a liquid-crystalline component C comprising    one or more compounds having a dielectric anisotropy of less than    −1.5, and the nematic liquid crystal mixture having a nematic phase    range of at least 60° C., a maximum viscosity at 20° C. of 30 mPa·s    and a mean dielectricity constant ε≦8.

Matrix liquid crystal displays (MLC displays) according to the preambleare known. For example, active elements (i.e. transistors) can be usedas non-linear elements for the individual switching of the individualpicture elements. This is referred to as an “active matrix”, in whichtwo types can be distinguished:

-   1. MOS (metal oxide semiconductor) transistors on a silicon wafer as    the substrate.-   2. Thin film transistors (TFT) on a glass plate as the substrate.

In the case of type 1, dynamic scattering or the guest/host effect isusually used as the electrooptical effect. The use of single-crystalsilicon as the substrate material limits the size of the display, since,even if different partial displays are put together in the form ofmodules, difficulties arise at the joints.

In the case of the more promising type 2, which is preferred, the TNeffect is usually used as the electro-optical effect. Two-technologiesare distinguished: TFTs consisting of compound semiconductors, such as,for example, CdSe, or TFTs based on polycrystalline or amorphoussilicon. The latter technology is the subject of intense developmentwork worldwide.

The TFT matrix is disposed on the inside surface of one of the glassplates of the display, while the other glass plate carries thetransparent counter electrode on its inside surface. Compared with thesize of the picture element electrode, the TFT is very small andessentially does not interfere with the picture. This technology canalso be extended to picture displays in fully satisfactory colours byarranging a mosaic of red, green and blue filters in such a manner thateach filter element is opposite to a switchable picture element.

The TFT displays usually operate as TN cells which contain crossedpolarizers in transmission and are illuminated from behind.

The term MLC displays in this context comprises each matrix displaywhich has integrated non-linear elements, i.e. apart from the activematrix also displays which contain passive elements such as varistors ordiodes (MIM=metal/insulator/metal).

MLC displays of this type are in particular suitable for TV applications(e.g. portable TVs) or for highly informative displays in automobile andaircraft construction. In addition to problems regarding the angledependency of the contrast and the switching times, difficulties in MLCdisplays arise from the insufficient resistivity of the liquid crystalmixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E.,SORIMACHI, K., TAJIMA, E., WATANABE, H., SHIMIZU, H., Proc. Eurodisplay84, September 1984: A 210-288 Matrix LCD Controlled by Double StageDiode Rings, p. 141 ff, Paris; STROMER, M., Proc. Eurodisplay 84,September 1984: Design of Thin-Film-Transistors for Matrix Addressing ofTelevision Liquid Crystal Displays, p. 145 ff, Paris]. With decreasingresistivity, the contrast of an MLC display deteriorates. Since theresistivity of the liquid crystal mixture usually decreases byinteraction with the inside surfaces of the displays over the lifetimeof an MLC display, a high (initial) resistance is very important forachieving acceptable service lives.

Therefore, there is still a high demand for MLC displays which have veryhigh resistivity in combination with a large range of operatingtemperatures, short switching times and low threshold voltage.

The object of the invention is to provide MLC displays which do not oronly to a small extent have the above disadvantages and, at the sametime, have very high resistivities.

It has now been found that this object can be achieved by using nematicliquid crystal mixtures in these display elements, which mixtures arebased on the abovementioned components A, B and C, B and C, or B.

Accordingly, the invention relates to an MLC display containing

-   -   two plane parallel support plates which together with a frame        form a cell,    -   integrated non-linear elements for switching individual picture        elements on the support plates and    -   a nematic liquid crystal mixture which is present in the cell        and has a positive dielectric anisotropy and high resistivity,        the liquid crystal mixture being based on the following        components:

-   a) at least 10% by weight of a liquid-crystalline component B    comprising one or more compounds having a dielectric anisotropy of    more than +1.5,

-   b) up to 90% by weight of a liquid-crystalline component A    comprising one or more compounds having a dielectric anisotropy of    −1.5 to +1.5 of the general formula I    in which

-   R¹ and R² are each, independently of one another, n-alkyl,    ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms,    -   the rings A¹, A² and A³        -   are each, independently of one another, 1,4-phenylene, 2- or            3-fluoro-1,4-phenylene, trans-1,4-cyclohexylene or            1,4-cyclohexenylene,    -   Z¹ and Z² are each, independently of one another, —CH₂CH₂— or a        single bond, and    -   m is 0, 1 or 2, and

-   c) 0 to 20% by weight of a liquid-crystalline component C comprising    one or more compounds having a dielectric anisotropy of less than    −1.5,    and the nematic liquid crystal mixture having a nematic phase range    of at least 60° C., a maximum viscosity at 20° C. of 30 mPa·s and a    mean dielectricity constant ε≦8.

The invention also relates to the corresponding liquid crystal mixtures,in particular for use in MLC displays. However, the mixtures are alsosuitable for many other applications, such as, for example, TN, STN orOMI.

Nematic liquid crystal mixtures which instead of the compounds of theformula I contain analogous compounds in which one of the radicals R¹and R² is n-alkyl and the other is n-alkoxy are known and commerciallyutilized in various designs. However, these liquid crystal mixtures aredistinguished by values for the resistivity which are too low and areoften between 5×10⁹ and 1.1×10¹¹ Ωcm or less at 20°. The correspondingMLC displays have values for the resistivity which are too low for somecommercial applications.

The resistivity of liquid crystal mixtures is in general high, if thedielectric anisotropy is small, since the polar components which arepresent in mixtures which have a high Δε have a stabilizing effect onions and thus lead to high conductivity or low resistance. Surprisingly,it has now been-found that the resistivity is particularly high, if themean dielectricity constant ε[=₃ ¹(2ε⊥+ε₁₁)] is small and, at the sametime, the dielectrically neutral (Δε from −1.5 to +1.5) components ofthe liquid crystal mixture do not contain any functional groups such as,for example, aromatically bound alkoxy or ester functions. Thedielectrically positive (Δε≧1.5) components usually carry terminal cyanogroups. However, in the mixtures according to the invention, it ispreferred to use, in addition to compounds which have a terminal cyano,also those which have a terminal —NCS, F, Cl, —CF₃′-CHF₂, —OCF₃, —OCHF₂,—OCF₂CF₂H or —OC₂F₅.

However, component B can also substantially consist only ofnitrile-containing compounds, of which those compounds of the formulaeIIa to IIf where X is CN are preferred. In this case, the liquid crystalmixture essentially consists of components A, B and C, or A and B.

Particular preference is given to liquid crystal mixtures which containnitrile-containing and nitrile-free, fluorinated compounds, the latterpreferably conforming to the formulae IIa to IIf in which X is F, Cl,—CF₃, —CHF₂, —OCF₃, —OCHF₂, —OCF₂CF₂H or —OC₂F₅.

The ratio of nitrile-free to nitrile-containing compounds in component Bis preferably >1:1, in particular >2:1. Particularly preferred rangesare 2.5:1 to 6:1.

However, very particular preference is given to liquid crystal mixtureswhose component B essentially consists of nitrile-free, fluorinatedcompounds. Preferably, the abovementioned preferred compounds of theformulae IIa to IIf are used.

‘Essentially’ is understood to mean that the amount of further compoundsin the corresponding component is ≦20%, in particular ≦10%.

Preference is also given to liquid crystal mixtures whose component Bcontains compounds whose end groups are chlorinated. Compounds of thistype are known to one skilled in the art and preferably conform to theformulae IIa to IIf where X is Cl. In a particularly preferredembodiment, the mixtures contain one or more compounds of the formulaIIa to IIf in which A²-X or A³-X is

where X is CF₃₁—OCF₃, —OCHF₂ or Cl. Furthermore, component B can alsocontain tetranuclear compounds, for example in accordance with formulaeIIc to IIf in which one of the rings A¹ to A³ is present twice.

In a particularly preferred embodiment, the mixtures contain compoundswhich have a terminal nitrile and are present in component B in anamount from 0 to 50% by weight. Particular preference is given tomixtures which do not contain any compounds which have a terminalnitrile. Surprisingly, it has been found that groups such as —OCF₃,—OCHF₂—, —OCF₂CF₂H or —OC₂F₅ have a considerably less stabilizing effectin the displays than —OCH, or —OC₂H₃. The same is true for aliphaticallybound alkoxy (compounds of the formulae III and IV).

The mixtures according to the invention preferably have a resistivity of≧10¹² Ω×cm, particularly preferably >10¹³ Ω×cm, at 20°. The mean ε ispreferably ≦7, in particular ≦5.

The values of dielectric anisotropy of the individual compounds ofcomponents A to C are determined at 20° by extrapolation from a polarmixture (containing 24% of p-trans-4-propylcyclohexylbenzonitrile, 36%of p-trans-4-pentylcyclohexylbenzonitrile, 25% ofp-trans-4-heptylcyclohexylbenzonitrile and 15% of4-cyano-4′-(trans-4-pentylcyclohexyl)biphenyl), if the compound to bedetermined contains a dipole along the longitudinal axis of themolecule, or from a neutral mixture (containing 22% oftrans-1-p-ethylphenyl-4-propylcyclohexane, 20% oftrans-1-p-methoxyphenyl-1-propylcyclohexane, 15% oftrans-1-p-ethoxyphenyl-4-propylcyclohexane, 19% of4-ethyl-4-(trans-4-propylcyclohexyl)biphenyl, 14% of4-ethyl-4-(trans-4-pentylcyclohexyl)biphenyl, 5% of4,4′-bis(trans-4-propylcyclohexyl)biphenyl and 5% of4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)biphenyl) inthe case of neutral compounds.

The liquid crystal mixtures according to the invention make it possibleto achieve a high value for the resistivity in combination with lowviscosities, which allows to produce excellent MLC displays. The MLCdisplays according to the invention preferably operate in the firsttransmission minimum according to Gooch and Tarry [C. H. Gooch and H. A.Tarry, Electron. Lett. 10, 2-4, 1974; C. H. Gooch and H. A. Tarry, Appl.Phys., Vol. 8, 1575-1584, 1975.], in which case in addition toparticularly favourable electrooptical properties such as, for example,high steepness of the characteristic curve and low angle dependence ofthe contrast (German Patent Specification 3,022,818) in combination withthe same threshold voltage as in an analogous display, a smallerdielectric anisotropy is sufficient in the second minimum. This makes itpossible to achieve significantly higher resistivities in the firstminimum, when the mixtures according to the invention are used.

The viscosity at 20° C. is preferably ≦25 mPa·s. The nematic phase rangeis preferably at least 70′, in particular at least 80°. Preferably, thisrange extends at least from −20° to +70′.

The individual compounds of the formulae I to IV and their subformulaewhich can be used in the MLC displays according to the invention areeither known or can be prepared analogously to known compounds.

Preferred liquid crystal mixtures to be used according to the inventioncontain a total of, preferably, 10% to 90%, in particular 20% to 90%, ofcompounds of the formula I. If component B is not composedpre-dominantly of strongly dielectrically positive nitrile componentsbut predominantly only of weakly dielectrically positive compounds suchas, for example, the fluorinated compounds mentioned below, component Acan under certain circumstances be omitted entirely, and the mixturesaccording to the invention can in this special embodiment be solelybased on component B and, if desired, component C. Particular preferenceis given to liquid crystal mixtures whose component B contains one ormore compounds selected from the group consisting of compounds of theformulae IIa to IIf

in which

-   R is n-alkyl or n-alkenyl of up to 9 carbon atoms,-   X is cyano, —NCS, F, Cl, —CF₃, —CHF₂, —OCF₃, —OCHF₂, —OCF₂CF₂H or    —OC₂F₃, and-   the rings A¹, A² and A³:    -   are each, independently of one another, 1,4-phenylene, 2- or        3-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene,        trans-1,4-cyclohexylene or 1,4-cyclohexenylene.

Preferably, component B contains compounds of the formulae IIa to IIf inwhich X is cyano and compounds of the formulae IIa to IIf in which X is—NCS, F, Cl, —CF₃, —CHF₂, —OCF₃′-OCHF₂, —OCF₂CF₂H or —OC₂F₅, and theamount of cyano compounds in component B is 0 to 50% by weight.

In a particularly preferred embodiment, component B does not contain anycompounds of the formulae IIa to IIf in which X is cyano.

In the compounds of the partial formulae IIa to IIf, X is preferably F,Cl, CF₃, —OCF₃, —OCHF₂ or —CHF₂.

The rings A¹, A² and A³ are each preferably, independently of oneanother, trans-1,4-cyclohexylene or 1,4-phenylene. In a preferredembodiment, one of the rings A¹, A² and A³ is 2- or3-fluoro-1,4-phenylene or 2,3-difluoro-1,4-phenylene. The ring bound toX (i.e. A² in IIa and IIb and A³ in IIc to IIf) is preferably1,4-phenylene which is unsubstituted or even mono- or di-substituted byfluorine. A²-X and A³-X are preferably a group selected from theformulae (a) to (h):

of which (a), (b), (d), (f), (g) and (h) are particularly preferred.

Particularly preferred smaller groups of compounds are listed below:

In the partial formulae IIa1 to IIf3, R is in each case n-alkyl orn-alkenyl of up to 9 carbon atoms) Y and Z are each, independently ofone another; H or F although one or two of the radicals Y and Z ispreferably fluorine. However, X is preferably F, Cl, —CF₃—, —OCF₃ or—OCHF₂.

Component B preferably represents 10% to 100%, in particular 20% to 80%,of the mixtures according to the invention.

Component A preferably contains one or more compounds selected from thegroup consisting of II1 to II7:

in which R¹ and R² have the meaning-given in claim 1.

Preferably, component A additionally contains one or more compoundsselected from the group consisting of II8 to II20:

in which R¹ and R² have the meaning given in claim 1 and the1,4-phenylene groups in II8 to II17 can each, independently of oneanother, also be mono- or polysubstituted by fluorine.

Furthermore, component A preferably additionally contains one or morecompounds selected from the group consisting of II21 to II25:

in which R¹ and R² have the meaning given; in claim 1 and the1,4-phenylene groups in II21 to II25 can each, independently of oneanother, also be mono- or polysubstituted by fluorine.

Finally, those mixtures are preferred whose component A contains one ormore-compounds selected from the group consisting of II26 and II27:

in which C_(x)H_(2x+1) is a straight-chain alkyl group of up to 7 carbonatoms.

In some cases, the addition of compounds of the formula

in which

-   R¹ and R² have the meaning given in claim 1 and-   Z⁰ is a single bond, —CH₂CH₂—,    proves to be advantageous for suppressing smectic phases, although    the resistivity is thereby lowered. Whether and in which amount    these compounds should be added for achieving optimum parameter    combinations for practical application can easily be determined by    one skilled in the art. Usually, less than 15%, in particular 5-10%,    are used.

Further preference is given to liquid crystal mixtures which, inaddition to components A, B and C, additionally contain one or morecompounds selected from the group consisting of III and IV:

in which R¹ and R² have the abovementioned meaning and/or one or morecompounds selected from the group consisting of V and VI

in which R¹ and R² have the abovementioned meaning and/or one or morecompounds selected from the group consisting of VII to XI

in which R¹ and R² have the abovementioned meaning and s is 0 or 1.

The amounts of the compounds of the formulae III to XI in the mixturesaccording to the invention (preferred ranges) can be seen from the tablebelow:

-   Sum of compounds III and IV: 0% to 40%, preferably 10% to 30%-   Sum of compounds V and VI: 0% to 40%, preferably 5% to 20%-   Sum of compounds VII to XI: 0% to 20%, preferably 5% to 15%

It goes without saying that the mixtures according to the invention,which preferably consist essentially of the compounds mentioned aspreferred for components A to C, may additionally also contain furthercompounds not mentioned here explicitly. However, this leads in manycases to more unfavourable properties. One skilled in the art can easilydetermine whether and in which amounts further compounds can be used.

The design of the MLC display according to the invention which consistsof polarizers, electrode base plates and electrodes which have beensubjected to surface treatment is that which is customary for this typeof display. The definition of customary design is in this case verybroad and also comprises all modifications and alterations of the MLCdisplay, in particular also matrix display elements based on poly-Si TFTor MIM.

However, a significant difference between the displays according to theinvention and those which have been customary so far and are based onthe twisted nematic cell is the selection of the liquid crystalparameters of the liquid crystal layer.

The preparation of the liquid crystal mixtures to be used according tothe invention is carried out in the usual manner. As a rule, the desiredamount of the components used in a minor amount is dissolved in thecomponents which constitute the major component, advantageously atelevated temperature. It is also possible to mix-solutions of thecomponents in an organic solvent, for example in acetone, chloroform ormethanol, and remove the solvent again after the mixing, for example bydistillation.

The dielectrics can also contain further additives known to one skilledin the art and described in the literature. For example, 0-15%pleochroic colorants or chiral doping substances can be added.

The examples which follow are intended to illustrate the inventionwithout limiting it. Hereinbefore and hereinafter all temperatures aregiven in ° C. The percentages are by weight.

EXAMPLE 1

A matrix liquid crystal display of the TFT type containing a nematicliquid crystal mixture consisting of

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of p-trans-4-butylcyclohexylbenzonitrile,-   22% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   9% of E-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluoro-biphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl    has a resistivity of 3×10¹² Ωcm. The nematic mixture has a clear    point of 91°, a viscosity of 18 mPa·s at 20°, a mean DC of 5.0 and    an optical anisotropy of 0.118.

EXAMPLE 2

A nematic mixture consisting of

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of p-trans-4-butylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   7% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   7% of 4-ethyl-41-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 93°, a viscosity of 19 mPa·s, a mean DC of 5.4,    a Δn of 0.107 and a resistivity of 2.5×10¹² Ωcm.

EXAMPLE 3

A nematic mixture consisting of

-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   17% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   3% of    4-(trans-4-pentylcyclohexyl)-41-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 88°, a viscosity of 15.2 mPa·s, a mean DC of    4.3, a Δn of 0.078 and a resistivity of 8.6×10¹³ Ωcm. This mixture    is particularly suitable for operation in the first minimum    according to Gooch and Tarry at a threshold voltage of 2.7 V.

EXAMPLE 4

A nematic mixture consisting of

-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   12% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl-ethane,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl)-2-(p-trifluoromethoxyphenyl)-ethane,    and-   4% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 91°, a Δn of 0.076, a mean DC of 4.2 and a    resistivity of 7.3×10¹³ Ωcm.

EXAMPLE 5

A nematic mixture consisting of

-   13% of p-trans-4-propylcyclohexylbenzonitrile,-   8% of p-trans-4-butylcyclohexylbenzonitrile,-   15% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   17% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 96°, a Δn of 0.103, a mean DC of 4.9 and a    resistivity of 1.0×10¹³ Ωcm. This mixture is particularly suitable    for operation in the first minimum according to Gooch and Tarry at a    threshold voltage of 2.3 V.

EXAMPLE 6

A nematic mixture consisting of

-   13% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   15% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   12% of    trans,trans-4-pentyl-4′-(2-fluoroethyl)-cyclo-hexylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 99°, a Δn of 0.097, a mean DC of 4.1 and a    resistivity of 7.8×10¹³ Ωcm. This mixture is particularly suitable    for operation in the first minimum according to Gooch and Tarry at a    threshold-voltage of 2.9 V.

EXAMPLE 7

A nematic mixture consisting of

-   16% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-41-fluoromethyl-cyclohexylcyclohexane,-   11% of    trans,trans-4-pentyl-41-(2-fluoroethyl)-cyclohexylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl    has a clear point of 99.5°, a Δn of 0.100, a mean DC of 4.2 and a    resistivity of 7.5×10¹³ Ωcm. This mixture is particularly suitable    for operation in the first minimum according to Gooch and Tarry at a    threshold voltage of 2.7 V.

EXAMPLE 8

A nematic mixture consisting of

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-41-fluoromethyl-cyclohexylcyclohexane,-   9% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   9% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 93.4°, a Δn of 0.108, a mean DC of 4.4 and a    resistivity of 1.3×10¹³ Ωcm. The viscosity at 20 is 18.4 mPa·s.

EXAMPLE 9

A nematic mixture consisting of

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   11% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   8% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 89.8°, a Δn of 0.102, a mean DC of 4.4, a    resistivity of 1.5×10¹³ Ωcm and a viscosity of 16.1 mPa·s.

EXAMPLE 10

A nematic mixture consisting of

-   8% of p-trans-4-propylcyclohexyl-fluorobenzene,-   7% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   8% of p-trans-4-hexylcyclohexyl-fluorobenzene,-   7% of p-trans-4-heptylcyclohexyl-fluorobenzene,-   5% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(2,3′,4′-trifluorobiphenyl-4-yl)-ethane,-   5% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(2,3′,4′-trifluorobiphenyl-4-yl)-ethane,-   8% of trans,trans-1-(p-ethylphenyl)-4-propyl-cyclohexylcyclohexane,-   7% of trans,trans-1-(p-propylphenyl)-4-pentyl-cyclohexylcyclohexane,-   8% of trans,trans-1-(p-fluorophenyl)-4-propyl-cyclohexylcyclohexane,-   7% of trans,trans-1-(p-fluorophenyl)-4-pentyl-cyclohexylcyclohexane,-   6% of    trans,trans-1-(p-trifluoromethoxyphenyl)-4-propyl-cyclohexylcyclohexane,-   4% of    trans,trans-1-(p-trifluoromethoxyphenyl)-4-pentyl-cyclohexylcyclohexane,-   6% of    trans,trans-1-[p-(1,1,2,2-tetrafluoroethoxy)-phenyl]-4-propyl-cyclohexylcyclohexane,-   4% of    trans,trans-1-[p-(1,1,2,2-tetrafluoroethoxy)-phenyl]-4-pentyl-cyclohexylcyclohexane,-   3% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   3% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and-   4% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl    has a clear point of 92°, a Δn of 0.099, a mean DC of 4.1, a    resistivity of 5.4×10¹³ Ωcm and a viscosity of only 14 mPa·s.

EXAMPLE 11

A nematic mixture consisting of

-   10% of p-trans-4-propylcyclohexylbenzonitrile,-   2.2% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   5% of 4,4′-bis-propylbiphenyl,-   5% of trans,trans-4-propyl-4′-methyl-cyclohexylcyclo-hexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   5% of 1,4-bis-(trans-4-propylcyclohexyl)-benzene,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   9% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   5% of    1-(trans-4-propylcyclohexyl)-2-(4′-ethyl-2′-fluorobiphenyl-4-yl)-ethane,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and,-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl,    has a clear point of 95°, a viscosity of 16 mPa·s, a Δn of 0.113, a    mean DC of 3.8 and a resistivity of 7×10¹³ Ωcm.

EXAMPLE 12

A nematic mixture consisting of

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   11% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   8% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of E[sic]-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl and-   6% of 4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl    cyclohexyl)-2-fluorobiphenyl    has a clear point of 90°, a viscosity of 18 mPa·s and a Δn of 0.102.

EXAMPLE 13

A nematic mixture consisting of

-   14% of p-trans-4-propylcyclohexylbenzonitrile,-   14% of trans-1-p-fluorophenyl-4-pentylcyclohexane,-   14% of trans-1-p-fluorophenyl-4-heptylcyclohexane,-   10% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   6% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   6% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   5% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   5% of 4,4′-bis-(trans-4-propylcyclohexyl)-biphenyl,-   5% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   5% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl,-   5% of 4,4′-bis-(trans-4-pentylcyclohexyl)-biphenyl,-   5% of    4-(trans-4-pentylcyclohexyl)-41-(trans-4-propyl-cyclohexyl)-biphenyl    and-   6% of    4-(trans-4-pentylcyclohexyl)-41-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl    has a clear point of 95°, a viscosity of 17 mPa·s and a Δn of 0.105.

The following mixtures are very suitable for MLC displays:

EXAMPLE 14

A nematic mixture is prepared which consists of:

-   10% of    1-(trans-4-pentylcyclohexyl)-2-(4′-fluoro-biphenyl-4-yl)-ethane,-   17% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl)-2-(p-trifluoromethylphenyl)-ethane,-   10% of    1-(trans-4-pentylcyclohexyl)-2-[trans-4-(3,4-difluorophenyl)-cyclohexyl]-ethane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   20% of    1-trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   3% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 15

A nematic mixture is prepared which consists of:

-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   12% of trans,trans-4-propyl-41-methoxymethyl-cyclohexylcyclohexane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl)-2-(3,4-difluorophenyl)-ethane,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   4% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 16

A nematic mixture is prepared which consists of:

-   13% of 1-(trans-4-propylcyclohexyl)-2-(p-cyanophenyl)-ethane,-   8% of    p-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl)-benzonitrile,-   18% of trans,trans-4-pentyl-41-fluoromethyl-cyclohexylcyclohexane,-   17% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   4% of    1-(trans-4-propylcyclohexyl)-2-(trans-4-pentyl-cyclohexyl)-ethane,-   4% of    1-(p-(trans-4-propylcyclohexyl-phenyl]-2-(trans-4-pentylcyclohexyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 17

A nematic mixture is prepared which consists of:

-   13% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   15% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   12% of 1-(trans-4-pentylcyclohexyl)-4-propylcyclohex-1-ene,-   4% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-4-propylcyclohex-1-ene,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexy)cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 18

A nematic mixture is prepared which consists of:

-   16% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   11% of    trans,trans-4-pentyl-4′-(2-fluoroethyl)-cyclohexylcyclohexane,-   4% of 1-(trans-4-propylcyclohexyl)-2-(4-pentyl-biphenyl-   4′-yl)-ethane,-   4% of    1-[p-(trans-4-pentylcyclohexyl)-phenyl]-2-(p-propylphenyl)-ethane,-   4% of    1-(trans-4-pentylcyclohexyl)-2-(trans-4-(p-propylphenyl)-cyclohexyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 19

A nematic mixture is prepared which consists of:

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-41-ethoxy-cyclohexylcyclohexane,-   13% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexylcyclohexane,-   9% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   9% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 20

A nematic mixture is prepared which consists of:

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of trans,trans-4-pentyl-4′-methoxy-cyclohexylcyclo-hexane,-   13% of trans,trans-4-propyl-4′-propoxy-cyclohexylcyclo-hexane,-   11% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   8% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   8% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propyl-cyclohexyl)-2-fluorobiphenyl.

EXAMPLE 21

A nematic liquid crystal mixture is prepared which consists of:

-   17% of p-trans-4-propylcyclohexylbenzonitrile,-   13% of p-trans-4-butylcyclohexylbenzonitrile,-   22% of trans-1-p-propylphenyl-4-pentylcyclohexane,-   4% of    1-(trans-4-propylcyclohexyl)-2-(4-ethyl-2,3-difluorobiphenyl-41-yl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   9% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   9% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of 4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)    -2-fluorobiphenyl.

EXAMPLE 22

A nematic mixture is prepared which consists of:

-   15% of p-trans-4-propylcyclohexylbenzonitrile,-   11% of p-trans-4-butylcyclohexylbenzonitrile,-   11% of trans,trans-4-pentyl-4′-fluoromethyl-cyclohexylcyclohexane,-   11% of trans,trans-4-propyl-4′-fluoromethyl-cyclohexyl-*    cyclohexane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-methylphenyl)-ethane,-   4% of 1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl-   2-(p-ethylphenyl)-ethane,-   4% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   4% of    1[-trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-pentylphenyl)-ethane,-   4% of 2-p-fluorophenyl-5-hexylpyrimidine,-   4% of 2-p-fluorophenyl-5-pentylpyridine,-   7% of 4-ethyl-4′-(trans-4-propylcyclohexyl)-biphenyl,-   7% of 4-ethyl-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl, and-   6% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl.

EXAMPLE 23

A nematic-mixture consisting of:

-   14% of p-trans-4-propylcyclohexylbenzonitrile,-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   10% of p-trans-4-heptylcyclohexyl-fluorobenzene,-   20% of p-trans-4-pentylcyclohexyl-difluoromethoxy -benzene,-   6% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   6% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   5% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane,-   5% of 4,4′-bis-(trans-4-propylcyclohexyl)-biphenyl,-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-biphenyl,-   5% of 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl,-   5% of 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl,-   5% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-biphenyl,    and-   5% of    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-2-fluorobiphenyl    has a clear point of 93°, a viscosity of 17 mPa·s, a Δn of 0.105 and    a high resistivity.

EXAMPLE 24

A nematic mixture consisting of

-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   10% of p-trans-4-hexylcyclohexyl-fluorobenzene,-   10% of p-trans-4-heptylcyclohexyl-fluorobenzene,-   20% of    p-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   10% of 4-trifluoromethoxy-4′-(trans-4-pentylcyclohexyl)-biphenyl    has a clear point of 80°, a Δn of 0.079, a threshold voltage    V_((10/0/20)) of 2.27 volt and a very low viscosity.

EXAMPLE 25

A nematic mixture consisting of

-   25% of p-trans-4-propylcyclohexyl-trifluoromethoxy-benzene,-   20% of 4-trifluoromethoxy-4′-(trans-4-pentylcyclohexyl)-biphenyl,-   15% of    p-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane    has a clear point of 54°, a Δn of 0.088, a threshold voltage    V_((10/0/20)) of 2.18 volt and a very low viscosity.

EXAMPLE 26

A nematic mixture consisting of

-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   10% of p-trans-4-hexylcyclohexyl-fluorobenzene,-   12% of p-trans-4-hexylcyclohexyl-difluoromethoxybenzene,-   10% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   11% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   11% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   11% of    1-trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   11% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    p-[trans-4-(trans-4-propylcyclohexyl]-trifluoro-methoxybenzene and-   4% of 4,4′-bis-(trans-4-pentylcyclohexyl)-biphenyl    has a clear point of 87°, a Δn of 0.0798; a dielectric anisotropy of    +6.5, a threshold voltage of V_((10/0/20)) of 2.25 volt and a very    low viscosity.

EXAMPLE 27

A nematic mixture consisting of

-   10% of p-trans-4-propylcyclohexyl-trifluoromethoxy-benzene,-   10% of p-trans-4-propylcyclohexyl-difluoromethoxy-benzene,-   10% of 1-(trans-4-(trans-4-pentylcylcohexyl)-[sic]-cyclohexyl)    -2-(p-trifluoromethylphenyl)-ethane,-   10% of 1-[trans-4-(trans-4-propylcylcohexyl)    [sic]-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   10% of    1-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-2-(p-fluorophenyl)-ethane,-   10% of 1-[trans-4-(trans-4-propylcylcohexyl)    [sic]-cyclohexyl]-2-(p-trifluoromethoxphenyl)-ethane,-   15% of 1-[trans-4-(trans-4-pentylcylcohexyl)    [sic]-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   10% of    1-[trans-4-(trans-4-propylcylcohexyl)[sic]-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,-   10% of    p-[trans-4-(trans-4-pentylcylcohexyl)[sic]-cyclohexyl]-trifluoromethoxybenzene    and-   5% of 4-trifluoromethoxy-4′-(trans-4-pentylcyclohexyl)-biphenyl    has a clear point of 81°, a Δn of 0.0795, a threshold voltage    V_((10/0/20)) of 2.47 volt and a very low viscosity.

EXAMPLE 28

A nematic mixture consisting of

-   10% of p-trans-4-propylcyclohexyl-trifluoromethoxy-benzene,-   25% of p-trans-4-pentylcyclohexyl-difluoromethoxy-benzene,-   15% of    p-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,-   15% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,-   15% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane,    and-   20% of 4-trifluoromethoxy-4′-trans-4-pentylcyclohexyl-biphenyl    has a clear point of 71°, a Δn of 0.0878, a Δε of +6.1, a threshold    voltage V_((10/0/20)) of 2.09 volt and a viscosity of 12 mPa·s at    20° C.

EXAMPLE 29

A nematic mixture consisting of

-   10% of p-trans-4-pentylcyclohexyl-fluorobenzene,-   15% of p-trans-4-hexylcyclohexyl-fluorobenzene,-   15% of p-trans-4-heptylcylcohexyl[sic]-fluorobenzene,-   20% of    p-(trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene,-   20% of    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    and-   20% of    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane,    has a clear point of 65°, a viscosity of 11 mPa·s at 20°, a Δn of    0.074, a Δε of +5.6 and a threshold voltage V_((10/0/20)) of 2.06    volt.

The composition of the mixtures of Examples 30 to 58 is given below, theindividual compounds being coded as follows:

-   PCH-301: trans-1-p-methoxyphenyl-4-propylcyclo-hexane-   CCH-301: trans,trans-4-methoxy-4′-propylcyclohexylcyclohexane-   CBC-33F: 4,4′-bis-(trans-4-propylcyclohexyl)-2-fluorobiphenyl-   CBE-55F: 4,4′-bis-(trans-4-pentylcyclohexyl)-2-fluorobiphenyl-   CBC-53F:    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclcohexyl)[sic]-2-fluorobiphenyl-   CBC-33: 4,4′-bis-(trans-4-propylcyclohexyl)-biphenyl-   CBC-55: 4,4′-bis-(trans-4-pentylcyclohexyl)-biphenyl-   CBC-53:    4-(trans-4-pentylcyclohexyl)-4′-(trans-4-propylcyclohexyl)-biphenyl-   ECCP-33:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-propylphenyl)-ethane-   CCH-51F: trans,trans-4-fluoromethyl-41-pentyl-cyclohexylcyclohexane-   CCH-31F: trans,trans-4-fluoromethyl-4′-propyl-cyclohexylcyclohexane-   PTP-102: 4-methyl-4′-ethoxy-tolan-   PTP-201: 4-methoxy-4′-ethyl-tolan-   CPTP-301: 4-(trans-4-propylcyclohexyl)-4′-methoxy-tolan-   CPTP-302: 4-(trans-4-propylcyclohexyl)-4-ethoxy-tolan-   CPTP-303: 4-(trans-4-propylcyclohexyl)-4′-propoxy-tolan-   PCH-5F: trans-1-p-fluorophenyl-4-pentylcyclohexane-   PCH-6F: trans-1-p-fluorophenyl-4-hexylcyclohexane-   PCH-7F: trans-1-p-fluorophenyl-4-heptylcyclohexane-   EPCH-20CF₃:    1(trans-4-ethylcyclohexyl)-2-(p-tri-fluoromethoxyphenyl)-ethane-   EPCH-30CF₃:    1-(trans-4-propylcyclohexyl)-2-(p-tri-fluoromethoxyphenyl)-ethane-   EPCH-50CF₃:    1-(trans-4-pentylcyclohexyl)-2-(p-tri-fluoromethoxyphenyl)-ethane-   EPCH-70CF₃:    1-(trans-4-heptylcyclohexyl)-2-(p-tri-fluoromethoxyphenyl)-ethane-   PCH-30CF₃: trans-1-p-trifluoromethoxyphenyl-4-propylcyclohexane-   PCH-50CF₃: trans-1-p-trifluoromethoxyphenyl-4-pentyl-cyclohexane-   ECCP-30CF₃:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane-   ECCP-50CF₃:    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethoxyphenyl)-ethane-   CCP-20CF₃:    p-trans-4-(trans-4-ethylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene-   CCP-30CF₃:    p-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene-   CCP-40CF₃:    p-[trans-4-(trans-4-butylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene-   CCP-50CF₃:    p-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-trifluoromethoxybenzene-   BCH-30CF₃: 4-trifluoromethoxy-4′-(trans-4-propylcyclohexyl)-biphenyl-   ECCP-3F.F:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane-   ECCP-5F.F:    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(3,4-difluorophenyl)-ethane-   CCP-3F.F:    4-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-1,2-difluorobenzene-   CCP-5F.F:    4-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-1,2-difluorobenzene-   CCP-3F:    4-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl)-fluorobenzene-   ECCP-3F:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane-   ECCP-5F:    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-fluorophenyl)-ethane-   CP-3F: p-fluorophenyl    trans-4-(trans-4-propylcyclohexyl)-cyclohexanecarboxylate-   CP-5F: p-fluorophenyl    trans-4-(trans-4-propylcyclohexyl)-cyclohexanecarboxylate-   PYP-5F: 2-p-fluorophenyl-5-pentylpyrimidine-   PYP-6F: 2-p-fluorophenyl-5-hexylpyrimidine-   PYP-7F: 2-p-fluorophenyl-5-heptylpyrimidine-   PYP-30CF₃: 2-p-trifluoromethoxyphenyl-5-propylpyrimidine-   PYP-50CF₃: 2-p-trifluoromethoxyphenyl-5-pentylpyrimidine-   PYP-70CF₃: 2-p-trifluoromethoxyphenyl-5-heptylpyrimidine-   PCH-3: p-trans-4-propylcyclohexyl-benzonitrile-   PCH-4: p-trans-4-butylcyclohexyl-benzonitrile-   PCH-5: p-trans-4-pentylcyclohexyl-benzonitrile-   ECCP-3:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-cyanophenyl)-ethane-   ECCP-3CF₃:    1-[trans-4-(trans-4-propylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane-   ECCP-5CF₃:    1-[trans-4-(trans-4-pentylcyclohexyl)-cyclohexyl]-2-(p-trifluoromethylphenyl)-ethane-   PYP-5N.F: 2-(3-fluoro-4-cyanophenyl)-5-pentylpyrimidine-   PYP-7N.F: 2-(3-fluoro-4-cyanophenyl)-5-heptylpyrimidine-   PCH-30CF₂: trans-1-p-difluoromethoxyphenyl-4-propylcyclohexane-   PCH-50CF₂: trans-1-p-difluoromethoxyphenyl-4-pentyl-cyclohexane-   PCH-30CF₂: trans-1-p-difluoromethoxyphenyl-4-propylcyclohexane-   PCH-53: trans-1-p-propylphenyl-4-pentylcyclohexane

EXAMPLE 30

PCH-301 10.00 PCH-7F 4.00 EPCH-30CF₃ 9.00 EPCH-7OCF₃ 5.00 CCP-30CF₃13.00 CCP-50CF₃ 12.00 ECCP-30CF₃ 12.00 ECCP-50CF₃ 8.00 ECCP-3F.F 12.00ECCP-3F 8.00 CBC-33F 2.00 CBC-53F 3.00 CBC-55F 2.00

EXAMPLE 31

PCH-30CF₂ 9.00 PCH-40CF₂ 8.00 PCH-50CF₂ 9.00 CCH-301 7.00 CCP-30CF₃13.00 CCP-50CF₃ 12.00 ECCP-30CF₃ 8.00 ECCP-50CF₃ 6.00 ECCP-3F.F 9.00ECCP-3F 6.00 CBC-33F 5.00 CBC-53F 4.00 CBC-55F 4.00

EXAMPLE 32

CCH-301 7.00 PCH-5F 12.00 PCH-7F 9.00 CCP-3OCF₃ 13.00 CCP-50CF₃ 12.00ECCP-30CF₃ 11.00 ECCP-50CF₃ 8.00 ECCP-3F.F 12.00 ECCP-3F 7.00 CBC-33F3.00 CBC-53F 3.00 CBC-55F 3.00

EXAMPLE 33

PCH-5F 13.0 PCH-7F 10.0 CCP-30CF₃ 13.0 CCP-40CF₃ 11.0 CCP-50CF₃ 12.0ECCP-30CF₃ 11.0 ECCP-50CF₃ 8.0 ECCP-3F.F 9.0 ECCP-5F.F 6.0 CBC-33F 3.0CBC-53F 2.0 CBC-55F 2.0

EXAMPLE 34

PCH-5F 11.0 PCH-6F 4.0 PCH-7F 10.0 CCP-20CF₃ 9.0 CCP-30CF₃ 13.0CCP-40CF₃ 7.0 CCP-50CF₃ 11.0 ECCP-30CF₃ 10.0 ECCP-50CF₃ 8.0 ECCP-3F.F8.0 CBC-33F 3.0 CBC-53F 3.0 CBC-55F 3.0

EXAMPLE 35

PCH-5F 13.0 PCH-7F 10.0 CCP-20CF₃ 10.0 CCP-30CF₃ 13.0 CCP-40CF₃ 7.0CCP-50CF₃ 11.0 ECCP-30CF₃ 11.0 ECCP-3F.F 10.0 ECCP-3F 8.0 CBC-33F 3.0CBC-53F 2.0 CBC-55F 2.0

EXAMPLE 36

PCH-5F 13.0 PCH-7F 10.0 CCP-20CF₃ 10.0 CCP-30CF₃ 13.0 CCP-40CF₃ 7.0CCP-50CF₃ 11.0 ECCP-30CF₃ 11.0 ECCP-3F.F 10.0 ECCP-5F.F 7.0 CBC-33F 3.0CBC-53F 3.0 CBC-55F 2.0

EXAMPLE 37

PCH-5F 13.0 PCH-7F 10.0 CCP-20CF₃ 10.0 CCP-30CF₃ 13.0 CCP-40CF₃ 7.0CCP-50CF₃ 11.0 ECCP-3F.F 10.0 ECCP-5F.F 8.0 ECCP-3F 11.0 CBC-33F 3.0CBC-53F 2.0 CBC-55F 2.0

EXAMPLE 38

PCH-5F 12.0 PCH-7F 10.0 CCP-20CF₃ 11.0 CCP-30CF₃ 13.0 CCP-40CF₃ 7.0CCP-50CF₃ 12.0 ECCP-30CF₃ 9.0 ECCP-3F.F 9.0 ECCP-5F.F 5.0 ECCP-3F 6.0CBC-33F 3.0 CBC-53F 2.0

EXAMPLE 39

PCH-5F 12.0 PCH-6F 9.0 PCH-7F 10.0 CCP-20CF₃ 11.0 CCP-30CF₃ 13.0CCP-40CF₃ 5.0 CCP-50CF₃ 12.0 ECCP-3F.F 9.0 ECCP-5F.F 5.0 ECCP-3F 5.0CBC-33F 3.0 CBC-53F 3.0 CBC-55F 3.0

EXAMPLE 40

PCH-5F 12.0 PCH-6F 8.0 PCH-7F 10.0 CCP-20CF₃ 11.0 CCP-30CF₃ 13.0CCP-40CF₃ 5.0 CCP-50CF₃ 12.0 ECCP-3F.F 11.0 ECCP-5F.F 8.0 CBC-33F 4.0CBC-53F 3.0 CBC-55F 3.0

EXAMPLE 41

PCH-5F 10.0 PCH-6F 5.0 PCH-7F 7.0 CCP-20CF₃ 11.0 CCP-30CF₃ 13.0CCP-40CF₃ 6.0 CCP-50CF₃ 11.0 ECCP-30CF₃ 7.0 ECCB-50CF₃ 3.0 ECCP-3F.F 9.0ECCP-5F.F 4.0 ECCP-5F 7.0 CBC-33F 3.0 CBC-53F 2.0 CBC-55F 2.0

EXAMPLE 42

PCH-3 19.0 PCH-7F 7.0 CCP-20CF₃ 11.0 CCP-30CF₃ 13.0 CCP-40CF₃ 6.0CCP-50CF₃ 12.0 ECCP-30CF₃ 7.0 ECCP-3F.F 10.0 ECCP-5F.F 8.0 ECCP-3F 7.0

EXAMPLE 43

PCH-3 20.00 PCH-4 8.00 PCH-5F 8.00 PCH-6F 8.00 PCH-7F 7.00 ECCP-3F 7.00ECCP-5F 7.00 CP-3F 12.00 CP-5F 12.00 ECCP-3 11.00

EXAMPLE 44

PCH-3 20.00 PCH-5F 9.00 PCH-6F 9.00 PCH-7F 9.00 ECCP-3F 8.00 ECCP-5F8.00 CP-3F 12.00 CP-5F 12.00 ECCP-3 13.00

EXAMPLE 45

PCH-3 14.00 PCH-5F 14.00 PCH-7F 14.00 PCH-53 10.00 ECCP-3F 6.00 ECCP-5F6.00 ECCP-3CF₃ 5.00 CBC-33 5.00 CBC-53 5.00 CBC-55 5.00 CBC-33F 5.00CBC-53F 6.00 CBC-55F 5.00

EXAMPLE 46

PCH-5F 20.00 PCH-6F 15.00 PCH-7F 15.00 ECCP-3F 10.00 ECCP-5F 10.00CBC-33 5.00 CBC-53 5.00 CBC-55 5.00 CBC-33F 5.00 CBC-53F 5.00 CBC-55F5.00

EXAMPLE 47

PCH-3 24.00 PCH-5F 9.00 PCH-7F 8.00 ECCP-3F 8.00 ECCP-5F 8.00 ECCP-30CF₃11.00 ECCP-50CF₃ 11.00 ECCP-3CF₃ 11.00 ECCP-3 10.00

EXAMPLE 48

PCH-3 24.00 PCH-5F 7.00 PCH-7F 6.00 CCH-31F 6.00 ECCP-3F 5.00 ECCP-5F5.00 ECCP-30CF₃ 11.00 ECCP-50CF₃ 11.00 ECCP-3CF₃ 11.00 ECCP-3 4.00 CP-3F5.00 CP-5F 5.00

EXAMPLE 49

PCH-3 24.00 CCH-31F 7.00 CCH-51F 7.00 ECCP-3F 8.00 ECCP-5F 8.00ECCP-30CF₃ 11.00 ECCP-50CF₃ 11.00 ECCP-3CF₃ 11.00 ECCP-3 13.00

EXAMPLE 50

PYP-5N.F 5.00 PYP-7N.F 5.00 PCH-3 14.00 PCH-5F 5.00 CCH-31F 7.00 CCH-51F7.00 ECCP-3F 5.00 ECCP-5F 5.00 ECCP-30CF₃ 11.00 ECCP-50CF₃ 11.00ECCP-3CF₃ 11.00 ECCP-3 4.00 CP-3F 5.00 CP-5F 5.00

EXAMPLE 51

PCH-5F 10.00 PCH-6F 12.00 PCH-7F 12.00 ECCP-3F 14.00 ECCP-5F 14.00 CP-3F15.00 CP-5F 15.00 ECCP-3 8.00

EXAMPLE 52

PCH-5F 10.00 PCH-6F 10.00 PCH-7F 10.00 ECCP-3F 13.00 ECCP-5F 14.00ECCP-3CF₃ 13.00 CP-3F 15.00 CP-5F 15.00

EXAMPLE 53

PCH-3 16.00 PCH-301 8.00 CCP-30CF₃ 9.00 CCP-50CF₃ 8.00 ECCP-30CF₃ 8.00ECCP-50CF₃ 7.00 ECCP-3F.F 7.00 ECCP-3F 6.00 ECCP-3CF₃ 7.00 BCH-30CF₃7.00 PTP-102 4.00 PTP-201 4.00 CPTP-301 2.00 CPTP-302 2.00 CPTP-303 3.00

EXAMPLE 54

PCH-3 18.00 PCH-301 8.00 PYP-3F 5.00 PYP-50CF₃ 5.00 PYP-70CF₃ 5.00CCP-30CF₃ 9.00 CCP-50CF₃ 8.00 ECCP-30CF₃ 8.00 ECCP-50CF₃ 7.00 ECCP-3F.F5.00 ECCP-3F 5.00 BCH-30CF₃ 7.00 CPTP-301 3.00 CPTP-302 3.00 CPTP-3034.00

EXAMPLE 55

PCH-3 20.00 PCH-301 10.00 PCH-30CF₂ 5.60 PCH-40CF₂ 5.60 PCH-50CF₂ 5.60CCP-30CF₃ 7.00 CCP-50CF₃ 6.30 ECCP-30CF₃ 6.30 ECCP-50CF₃ 5.60 ECCP-3F.F5.60 ECCP-3CF₃ 5.60 BCH-30CF₃ 7.00 CPTP-301 3.50 CPTP-302 2.80 CPTP-3033.50

EXAMPLE 56

PCH-3 20.00 PCH-301 10.00 PYP-3F 5.60 PYP-5F 5.60 PYP-50CF₃ 5.60PYP-70CF₃ 5.60 CCP-30CF₃ 7.00 CCP-50CF₃ 6.30 ECCP-30CF₃ 6.30 ECCP-50CF₃5.60 ECCP-3F.F 5.60 ECCP-3CF₃ 5.60 CPTP-301 3.50 CPTP-302 3.50 CPTP-3034.20

EXAMPLE 57

PCH-3 18.00 PCH-5F 12.00 PCH-6F 12.00 PCH-7F 10.00 ECCP-3F 7.00 ECCP-5F7.00 ECCP-33 5.00 CBC-33 5.00 CBC-53 5.00 CBC-55 4.00 CBC-33F 5.00CBC-53F 5.00 CBC-55F 5.00

EXAMPLE 58

PCH-3 10.00 PCH-5F 18.00 PCH-6F 14.00 PCH-7F 10.00 ECCP-3F 9.00 ECCP-5F7.00 CBC-33 5.00 CBC-53 6.00 CBC-55 5.00 CBC-33F 5.00 CBC-53F 6.00CBC-55F 5.00

The properties of the mixtures from Examples 30 to 58 are listed in thetable below: Example Property 30 31 32 33 34 35 36 37 38 39 Clear point[° C.] 100 101 100 103 100 101 101 100 101 88 Vicosity at 20° 15 15 1515 15 14 (mPa · s) Δε +4.0 +6.6 +5.9 +4.0 +4.6 +4.0 ε₁₁ 7.0 6.8 7.5 6.9Δn 0.090 0.090 0.084 0.076 0.087 0.084 0.085 0.081 0.081 0.091V_((10,0,20))[volt] 2.44 2.40 2.57 2.52 2.27 2.29 2.20 2.26 2.27 2.13Example Property 40 41 42 43 44 45 46 47 48 49 Clear point [° C.] 90 10298 82 84 95 89 87 84 101 Vicosity at 20° 14 15 17 18 18 17 15 16 16 20(mPa · s) Δε +4.0 +3.9 +8.0 +7.3 +4.6 +2.7 +8.7 +7.9 +8.3 ε₁₁ 7.0 6.611.9 11.0 7.6 12.1 11.5 11.8 Δn 0.079 0.081 0.090 0.094 0.090 0.1050.093 0.094 0.089 0.094 V_((10,0,20))[Volt] 2.20 2.33 1.90 1.71 1.752.15 2.98 1.82 1.86 1.98 Example Property 50 51 52 53 54 55 56 57 58Clear point [° C.] 85 94 94 106 91 81 73 95 94 Vicosity at 20° 19 17 1717 (mPa · s) Δε +10.2 +6.9 +8.1 +6.5 +8.7 +5.2 ε₁₁ 14.2 10.4 11.8 10.812.8 8.4 Δn 0.096 0.074 0.072 0.132 0.125 0.113 0.125 0.105 0.101V_((10,0,20))[Volt] 1.56 2.42 2.58 2.51 2.12 2.15 1.85 2.03 2.23

Further mixtures according to the invention are listed below:

EXAMPLE 59

CCH-301 7.00 PCH-5F 12.00 PCH-7F 9.00 CCP-3F.F 13.00 CCP-5F.F 12.00ECCP-30CF₃ 11.00 ECCP-50CF₃ 8.00 ECCP-3F.F 12.00 ECCP-3F 7.00 CBC-33F3.00 CBC-53F 3.00 CBC-55F 3.00

EXAMPLE 60

PCH-5F 13.0 PCH-7F 10.0 CCP-30CF₃ 13.0 CCP-40CF₃ 11.0 CCP-50CF₃ 12.0ECCP-30CF₃ 11.0 ECCP-50CF₃ 8.0 CCP-3F.F 9.0 CCP-5F.F 6.0 CBC-33F 3.0CBC-53F 2.0 CBC-55F 2.0

EXAMPLE 61

PCH-5F 11.0 PCH-6F 4.0 PCH-7F 10.0 CCP-20CF₃ 9.0 CCP-30CF₃ 13.0CCP-40CF₃ 7.0 CCP-50CF₃ 11.0 CCP-3F.F 10.0 CCP-5F.F 8.0 CCP-3F 8.0CBC-33F 3.0 CBC-53F 3.0 CBC-55F 3.0

EXAMPLE 62

PCH-3 20.0 PCH-4 8.0 PCH-5 8.0 PCH-6F 8.0 PCH-7F 7.0 CCP-3F.F 7.0CCP-5F.F 7.0 CP-3F 12.0 CCP-3F 12.0 ECCP-3 11.00

EXAMPLE 63

PCH-3 14.00 PCH-5F 14.00 PCH-7F 14.00 PCH-53 10.00 CCP-3F 6.00 CCP-5F6.00 CCP-3F.F 5.00 CBC-33 5.00 CBC-53 5.00 CBC-55 5.00 CBC-33F 5.00CBC-53F 6.00 CBC-55F 5.00

EXAMPLE 64

PCH-5F 20.00 PCH-6F 15.00 PCH-7F 15.00 CCP-3F.F 10.00 CCP-5F.F 10.00CBC-33 5.00 CBC-53 5.00 CBC-55 5.00 CBC-33F 5.00 CBC-53F 5.00 CBC-55F5.00

EXAMPLE 65

PCH-3 16.00 PCH-301 8.00 CCP-30CF₃ 9.00 CCP-50CF₃ 8.00 CCP-3F.F 8.00CCP-5F.F 7.00 ECCP-3F.F 7.00 CCP-3F 6.00 ECCP-3CF₃ 7.00 BCH-30CF₃ 7.00PTP-102 4.00 PTP-201 4.00 CPTP-301 2.00 CPTP-302 2.00 CPTP-303 3.00

EXAMPLE 66

PCH-3 18.00 PCH-5F 12.00 PCH-6F 12.00 PCH-7F 10.00 CCP-3F.F 7.00CCP-5F.F 7.00 ECCP-33 5.00 CBC-33 5.00 CBC-53 5.00 CBC-55 4.00 CBC-33F5.00 CBC-53F 5.00 CBC-55F 5.00

EXAMPLE 67

PCH-3 10.00 PCH-5F 18.00 PCH-6F 14.00 PCH-7F 10.00 CCP-3F.F 9.00CCP-5F.F 7.00 CBC-33 5.00 CBC-53 6.00 CBC-55 5.00 CBC-33F 5.00 CBC-53F6.00 CBC-55F 5.00

EXAMPLE 68

Composition: PCH-3 10.0% PCH-5F 18.0% PCH-6F 14.0% PCH-7F 10.0% ECCP-3F9.0% ECCP-5F 7.0% CBC-33 5.0% CBC-53 6.0% CBC-55 5.0% CBC-33F 5.0%CBC-53F 6.0% CBC-55F 5.0% S → N <−20° C. Clearing point +94° C.Viscosity ν +20° C. 16 mm² s⁻¹ Dielectric anisotropy Δε 1 kHz, 20° C.+4.1 ε_(∥) 1 kHz, 20° C. 7.1 ε_(⊥) 1 kHz, 20° C. 3.0 Optical anisotropyΔn +0.1006 (20° C., 589 nm) n 1.5932 n 1.4926

EXAMPLE 69

Composition: PCH-3 18.0% PCH-5F 12.0% PCH-6F 12.0% PCH-7F 10.0% ECCP-3F7.0% ECCP-5F 7.0% ECCP-33 5.0% CBC-33 5.0% CBC-53 5.0% CBC-55 4.0%CBC-33F 5.0% CBC-53F 5.0% CBC-55F 5.0% S → N <−40° C. Clearing point+95° C. Viscosity ν +20° C. 17 mm² s⁻¹ Dielectric anisotropy Δε 1 kHz,20° C. +5.2 ε_(∥) 1 kHz, 20° C. 8.4 ε_(⊥) 1 kHz, 20° C. 3.2 Opticalanisotropy Δn +0.1050 (20° C., 589 nm) n 1.5981 n 1.4931

EXAMPLE 70

Composition: PCH-3 7.0% PCH-5F 12.0% PCH-6F 12.0% PCH-7F 10.0% ECCP-3F7.0% ECCP-5F 7.0% PCH-53 8.0% ECCP-33 5.0% CBC-33 5.0% CBC-53 6.0%CBC-55 5.0% CBC-33F 5.0% CBC-53F 6.0% CBC-55F 5.0% S → N <−20° C.Clearing point +98° C. Viscosity ν +20° C. 16 mm² s⁻¹ Dielectricanisotropy Δε 1 kHz, 20° C. +3.2 ε_(∥) 1 kHz, 20° C. 6.0 ε_(⊥) 1 kHz,20° C. 2.8 Optical anisotropy Δn +0.1008 (20° C., 589 nm) n 1.5942 n1.4934

Exemples 71 72 S − N [° C.] <0 <0 Clearing point +100 +101 [° C.]Viscosity 16 16 [mm²s⁻¹] 20° C. Δ

(20° C., +0.086 +0.086 589 nm) n (20° C., 1.558 1.556 589 nm)V_((10,0,20)) 2.33 2.38 V_((50,0,20)) 2.86 2.92 V_((20,0,20)) 3.52 3.62Composition EPCH-3OCF3 13.0 EPCH-3OCF3 13.0 [%]: PCH-TF 10.0 EPCH-

OCF3 10.0 CCP-2OCF3 10.0 CCP-2OCF3 10.0 CCP-3OCF3 13.0 CCP-3OCF3 13.0CCP-4OCF3 7.0 CCP-4OCF3 7.0 CCP-

OCF3 11.0 CCP-

OCF3 11.0 ECCP-3F.F 10.0 ECCP-3F.F 10.0 ECCP-3F.F 4.0 ECCP-3F.F 4.0ECCP-3F 11.0 ECCP-3F 11.0 CBC-33F 3.0 CBC-33F 3.0 CBC-43F 2.0 CBC-

3F 2.0 CBC-

F 2.0 CBC-

F 2.0

The liquid crystal mixtures according to the invention can contain, inaddition to component B and, where present, A and C, still furtheradditives such as, for example, chiral doping substances, isotropicadditives for modifying various parameters, pleochroic dyes and thelike. Components A, B and C preferably comprise predominantly thecompounds mentioned (that is, more than 50%, in particular more than60%, of them). However, in a preferred manner, components A, B and Ccomprise the compounds mentioned (that is, more than 80%, in particular100% of them).

1. A matrix liquid crystal display comprising: two plane parallelsupport plates which together with a frame form a cell, integratednon-linear elements for switching individual picture elements on thesupport plates and a nematic liquid crystal mixture which is present inthe cell and has a positive dielectric anisotropy and high resistivity,wherein the liquid crystal mixture is based on the following components:a) at least 10% by weight of a liquid-crystalline component B comprisingone or more compounds of the formulae:

wherein R is n-alkyl or n-alkenyl of up to 9 carbon atoms, X is —CF₃,—OCF₃, or —OCHF₂, and the rings A¹ and A² are each, independently of oneanother, 1,4-phenylene, 2- or 3-fluoro-1,4-phenylene,2,3-difluoro-1,4-phenylene, trans-1,4-cyclohexylene or1,4-cyclohexenylene, and/or b) up to 90% by weight of aliquid-crystalline component A comprising one or more compounds having adielectric anisotropy of −1.5 to 1.5 of the general formula I

wherein R¹ and R² are each, independently of one another, n-alkyl,ω-fluoroalkyl or n-alkenyl having up to 9 carbon atoms, the rings A³ andA⁴ are each, independently of one another, 1,4-phenylene, 2- or 3fluoro-1,4-phenylene, trans-1,4-cyclohexylene or 1,4-cyclohexenylene,and Z¹ is —CH₂CH₂— or a single bond, and the nematic liquid crystalmixture has a nematic phase range of at least 60° C., a maximumviscosity at 20° C. of 30 mPa·s and a mean dielectricity constant ε≦8.2. A display according to claim 1, wherein the liquid crystal mixturecomprises one or more compounds of formulae IIa and/or IIb.
 3. A displayaccording to claim 1, wherein the liquid crystal mixture comprises oneor more compounds of formula Ia, wherein

are both selected from trans-1,4-cyclohexylene or 1,4-cyclohexenylene,or one or both of them are selected from 1,4-phenylene, 2- or3-fluor-1,4-phenylene or 2,3-difluor-1,4-phenylene.
 4. A displayaccording to claim 1, wherein the liquid crystal mixture comprises oneor more compounds of formula IIa, wherein one of

is 1,4-phenylene, 2- or 3-fluor-1,4-phenylene or2,3-difluor-1,4-phenylene.
 5. A display according to claim 1, whereinthe liquid crystal mixture comprises one or more compounds of formulaIIa, wherein one of

is 2- or 3-fluor-1,4-phenylene.
 6. A display according to claim 2,wherein

are, independently, trans-1,4-cyclohexylene or 1,4-cyclohexenylene.
 7. Adisplay according to claim 2, wherein one or both of

is trans-1,4-cyclohexylene.
 8. A display according to claim 1, whereinthe liquid crystal mixture comprises one or more compounds of formulaIIa wherein X is OCF₃ or CF₃.
 9. A display according to claim 1, whereinthe liquid crystal mixture comprises one or more compounds of formulaIIa wherein X is CF₃.
 10. A display according to claim 1, wherein theliquid crystal mixture comprises one or more compounds of formula I,wherein

are both trans-1,4-cyclohexylene or 1,4-cyclohexenylene.
 11. A displayaccording to claim 1, wherein the liquid crystal mixture comprises oneor more compounds of formula I, wherein

are both trans-1,4-cyclohexylene.
 12. A display according to claim 1,wherein the liquid crystal mixture comprises one or more compounds offormula I, wherein R¹ and R² are each, independently, n-alkyl orn-alkenyl.
 13. A display according to claim 1, wherein the liquidcrystal mixture comprises one or more compounds of formula I, whereinboth R¹ and R² are alkyl.
 14. A display according to claim 1, whereinthe liquid crystal mixture comprises one or more compounds of formula I,wherein one of R¹ and R² is n-alkyl and the other is n-alkenyl.
 15. Adisplay according to claim 1, wherein the liquid crystal mixturecomprises one or more compounds of formula I, wherein both R¹ and R² arealkenyl.